The main signs that precede a girl’s first menstrual period are the development of secondary sexual characteristics and an increase in vaginal discharge. 1. After puberty, the breasts begin to develop and, over time, they become noticeably larger and areolas appear. Under the influence of hormones in the body, most girls will begin to grow pubic hair. Generally, girls will menstruate within one or two years after the appearance of secondary sexual characteristics such as breast development and pubic hair growth. 2. Before puberty, normal girls have no or very little vaginal discharge. When a girl enters puberty, the presence of a thick, colorless, odorless, clear, egg-white-like discharge from the vagina generally indicates that the first menstrual period may occur in the near future. In addition, the girl’s first menstrual sign, there may also be growth acceleration, even up to 10-15cm a year.